Conjunctivitis is the most common eye disorder and may vary in severity from a mild inflammation with tearing to a severe inflammation that causes tissue injury. Infectious conjunctivitis is generally caused by the presence of bacteria or viruses. A variety of bacteria may cause bacterial conjunctivitis, such as S. pneumoniae, H. influenzae, P. aeruginosa, or S. pyogenes. Likewise, a variety of viruses may be responsible for viral conjunctivitis, such as adenovirus, herpes simplex virus (HSV), varicella-zoster virus (VZV), picornavirus (enterovirus 70, Coxsackie A24), poxvirus (molluscum contagiosum, vaccinia), and human immunodeficiency virus (HIV). Adenoviral conjunctivitis is the most common cause of viral conjunctivitis. Particular subtypes of adenoviral conjunctivitis include epidemic keratoconjunctivitis (pink eye) and pharyngoconjunctival fever. Primary ocular herpes simplex infection is also common, particularly in children, and is normally associated with a follicular conjunctivitis.
The treatment protocol for infectious conjunctivitis largely depends on whether the infection is viral or bacterial. Viral conjunctivitis is self-limiting and may require no specific treatment, other than drops to alleviate any symptoms associated with the infection. On the other hand, patients having bacterial conjunctivitis are typically treated with topical antibiotics (e.g., sulfacetamide sodium 10% drops or trimethoprim/polymyxin B qid). Conventional techniques for diagnosing the type of ocular infection rely primarily on clinical examination. For example, because the discharge in bacterial conjunctivitis is usually more purulent than the watery discharge of viral conjunctivitis, physical examination may be used in the diagnosis. Unfortunately, such diagnostic techniques are often unreliable and lead to the prescription of antibiotic drops in cases in which they are not needed.
As such, a need currently exists for a technique of rapidly screening for bacterial conjunctivitis in a patient.